Guide · First aid

Diarrhoea and rehydration

Diarrhoea is common after drinking unsafe water or eating contaminated food. The biggest danger is losing too much water and salt, especially for babies, young children and older people. Seek medical help urgently for signs of severe dehydration, blood in the stool, or a baby with diarrhoea who isn't feeding.

Signs of dehydration

• Mild to moderate: thirst, dark urine, passing less urine, dry mouth, tiredness, headache, dizziness.
• Severe: very little or no urine, sunken eyes, cold hands and feet, fast heartbeat, drowsiness, confusion. In babies, a sunken soft spot on the head and no wet nappies for several hours.

Rehydration

Oral rehydration solution (ORS) replaces water, salt and sugar in the right balance. Use ready-made sachets if you have them, mixed exactly as instructed.

If you have none, make your own:

1. Take 1 litre of safe drinking water (boiled and cooled if in doubt).
2. Add 6 level teaspoons of sugar.
3. Add half a level teaspoon of salt.
4. Stir until dissolved. Taste it: it should be no saltier than tears.

Measure carefully. Too much salt can be harmful, especially for children.

How to give it

• Sip small amounts often, rather than large amounts at once.
• If they vomit, wait 10 minutes, then start again more slowly — a spoonful every minute or two.
• Aim to give a cupful after each loose stool on top of normal drinking. Adults may need 2–3 litres a day or more.
• Keep breastfeeding babies, and feed more often.
• Make up fresh solution each day.

Eating

Start eating normally as soon as they feel able. Simple foods such as rice, bread, bananas, porridge and soup are easy on the stomach. Children should keep eating to stay strong.

Medicines

Anti-diarrhoea tablets can help adults in an emergency, but don't use them if there is blood in the stool or a high fever, and don't give them to young children.

Prevent it spreading

• Wash hands with soap after using the toilet and before handling food.
• Keep toilets well away from water sources and food.
• Treat all drinking water.
• Don't let someone with diarrhoea prepare food for others.

Get medical help if

• There are signs of severe dehydration
• There is blood or mucus in the stool, or a high fever
• They can't keep any fluids down
• Diarrhoea lasts more than a day in a baby, or more than a few days in an adult
• They are very young, elderly, pregnant or already unwell

This guide does not replace a first-aid course. A few hours of hands-on practice will make you far more confident when it matters.

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